Most often a team having to give up their homegrown star is given as an example of things being wrong, you're saying that you like that about football ? That's a different angle.
The problem with MLB versus NFL is that baseball teams receive vastly different amounts for their local media rights. The difference in ticket revenue from city to city also contributes to the revenue gap but not as much. In the NFL they all get an equal amount from media rights and pretty close for ticket revenue. Everyone starting with the same revenue is why the NFL is competitive, not the convoluted salary cap.
Also, I'm a Yankee fan for the same reason 99% of people like their respective teams : geography. I grew up in NYC and took the subway to Yankees all the time as a kid.